This is a valuable quality in a critic. Besides reflecting high standards, it is dramatic. Shales made whatever he wrote about seem to have stakes, even if it was “Family Feud.” And that in turn made you care about game show hosts and comics and news anchors in a way you didn’t before, even if he panned them.

When critics die, people tend to point to the things they got right or wrong, as if that were the measure. It isn’t, though a case on that count could be made for Shales. He championed “Cheers,” “Twin Peaks,” “The Sopranos.” He applied critical rigor to comedy specials when there weren’t many, and he understood early that whatever you think about “Full House,” it works.

Unlike Kael or Tynan, Shales wasn’t at his best beating the drum for or against something. All his work maintained a skeptical, knowing, light comic style. He always had more passion for the form than for any artist in it. This could lead to brutal honesty. He annually mocked Kathie Lee Gifford’s holiday special with sadistic glee, and while I would like to defend his famous pan of “Late Night With Conan O’Brien” (which even the talk show host admitted decades later was accurate), its dismissive harshness blinds him to the peculiar ambition the green host displayed. (He eventually changed his mind and wrote a rave about O’Brien years later.)

Brutal negative criticism is now out of fashion, but it’s too much a part of the human experience to be killed off. It just migrated online. Less casual cruelty is a good thing, but there are real risks to this new politeness. A critic is a kind of reporter, one whose beat requires pacing between mind and gut, filing dispatches filtered through an intellectual apparatus. Once you stop reporting what is there, you cease being useful. Shales never did.

When I was growing up in Washington D.C., I didn’t realize my luck that the most influential criticism on late night television was being done in my local paper. Shales loved David Letterman and that surely rubbed off on me. I never met Shales, but when I thanked him for reviewing my biography of David Letterman, he was kind enough to regale me with some war stories, and this advice: “Try not to let The Times suffocate you.”

Critics rarely end their careers well. Perhaps this will be of some solace to wounded artists. Shales felt he was pushed out at The Washington Post — he told me (plausibly) that he was a victim of the “cyber apocalypse.” But I didn’t find his message to be bitter, or at least not only that.

Criticism is among other things an act of vulnerability. Regularly putting your views out into the world to be picked apart, doing the intrepid thinking, fast writing and enemy-making that is a part of the job while holding onto your sensitivity, curiosity and confidence — it’s harder than it looks. Sometimes you fail or, worse, cut corners. But what I took Tom Shales to mean, in his advice to me, was that the thing you must protect, what requires expending courage on, is your own voice. It’s good advice, worth passing on.